#include<iostream>

using namespace std;
class A 
{ 
	public: 
	int _a;
};

class B : virtual public A { 
	public: 
	int _b; 
};

class C : virtual public A { 
	public: 
	int _c; 
};

class D : public B, public C {
	public: 
	int _d; 
};

int main()
{
	D d;
	d._b = 1;
	d._c = 2;
	d._d = 3;
	d._a = 4;

	return 0;

}